Dogs exhibit behavioural heterogeneity as a result of their close proximity to people as pets, working animals, or research animals. This variability stems from their natural talents as well as contextual effects. This document examines the several types of dog behavioural tests, including those that are used to evaluate dogs and others that are used to categorize individual animals. This study revealed a lack of agreement on all of these testing procedures. Individual variations in behaviour, or personality differences, may now be quantified and described in the working dog literature. The predictive association between certain dog behavioural features (if any) and crucial working results is less well-known.